1. Field of the Invention
The invention relates to concrete vibration devices and more particularly to a battery powered concrete vibrator.
2. Description of Related Art
Optimum oscillation frequency of a concrete vibrator is 200 Hz. Typically, there are two types of concrete vibrator available. One has an eccentric rotor which eccentrically rotates about a center of rotation in a casing so that vibration can be provided. However, it is disadvantageous due to excessive noise and unstable oscillation frequency in the range of 60 to 150 Hz. The other has a variable-frequency drive for changing frequency from 50 Hz to 200 Hz. It further includes an internal electric motor and an unbalanced mass. The motor imparts rotation to the unbalanced mass to vibrate a concrete after being regulated by the variable-frequency drive. Its advantages include low noise and high performance. Its drawbacks include reduced intensity of vibration and prohibitively high manufacturing cost. Thus, the need for improvement still exists.